Non-uniform illumination in low concentration photovoltaic systems based on small-scale linear Fresnel reflectors

Low concentration photovoltaic systems improve performance by absorbing and concentrating more sunlight than non-concentration ones. However, they require uniform illumination of the PV cells, as their electrical performance can decrease dramatically otherwise. A thorough analysis of the design causes of non-uniform illumination in small-scale linear Fresnel reflectors (SSLFR) is carried out, yielding the main parameters to be optimized. Then, such an optimized SSLFR guaranteeing uniform illumination is designed, and an optimum operation interval is estimated during which, furthermore, neither shading nor blocking on the mirrors happens. The study requires computing the maximum optimal transverse incidence angle, θt0, whose influence on the time-span of optimum operation, width of the SSLFR, annual solar irradiation, width of the mirrors, and position of the mirrors is also studied. We include a detailed example showing the accuracy of our calculations, using Monte Carlo Ray Tracing. •An analysis of the design causes of non-uniform illumination in SSLFR is presented.•An optimized SSLFR guaranteeing uniform illumination is designed.•We include a detailed example using Monte Carlo Ray Tracing.